scholarly journals Synthesis, Characterization, and Photocatalytic Activity of ZnO Nanomaterials Prepared by a Green, Nonchemical Route

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Ngoc Thinh Nguyen ◽  
Van Anh Nguyen
Keyword(s):  
Uv Light ◽  
Photocatalytic Decomposition ◽  
Illumination Time ◽  
Reaction Rate Constants ◽  
Uv Illumination ◽  
Zno Nanomaterials ◽  
Crystallite Sizes ◽  
Size And Morphology ◽  
Analytical Tools ◽  
Synthesized Materials

An eco-friendly method for the synthesis of ZnO nanoparticles was studied. Zinc acetate precursor was thermally decomposed without adding any chemical agents. The synthesized materials were thoroughly characterized by various analytical tools. The results indicated that the synthesized ZnO nanomaterials have a wurtzite structure. The estimated crystallite sizes of the materials obtained at 450, 550, 650, and 750°C (named as ZnO-450, ZnO-550, ZnO-650, and ZnO-750) were 33, 36, 38, and 42 nm, respectively. The morphology of the nanomaterials was revealed to be affected by calcination temperature, causing the formation of both nanoparticles and nanorods with different sizes and shapes. The materials were applied as photocatalysts for methylene blue (MB) decomposition under ultraviolet (UV) light. Results showed that the decomposition efficiency strongly depends on UV illumination time, size, and morphology of ZnO nanomaterials. The highest MB decomposition (99.4%) is obtained when using ZnO-750. The photocatalytic decomposition follows the first-order reaction. The reaction rate constants corresponding to the MB decomposition process with the presence of ZnO-450, ZnO-550, ZnO-650, and ZnO-750 are 0.0512, 0.0636, 0.1077, and 0.1286 min-1, respectively.

Bactericidal Effect of TiO2 on the Selected Vibrio Parahaemolyticus and Optimization Using Response Surface Methodology

2007 ◽  
Vol 7 (11) ◽  
pp. 3709-3712
Author(s):  
Tae-Young Kim ◽  
Kyung-Hee Park ◽  
Seon-Gyun Rho ◽  
Seung-Jai Kim ◽  
Sung-Young Cho
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Vibrio Parahaemolyticus ◽  
Pathogenic Bacteria ◽  
Uv Light ◽  
Bactericidal Effect ◽  
Illumination Time ◽  
Box Behnken Design ◽  
Uv Illumination ◽  
Typical Food

In this work, the bactericidal effect of TiO2 on selected typical food pathogenic bacteria, Vibrio parahaemolyticus was studied. V. parahaemolyticus is an important pathogen of humans and aquacultured animals. We established the response surface methodology (Box-Behnken Design) to investigate the effect of principal parameters on the cell sterilization such as TiO2 concentration, UV illumination time, temperature, and pH. The sterilization rate reached maximum value at the TiO2 concentration of 1.0 mg/ml. During irradiation under the time of 30 min with UV light with the 1g-TiO2/l, the sterilization rate was greater than 85%, and 99% or more cell lost their viability with 3 hours of irradiation. Sterilization rate of the cell increased with decrease in the pH and temperature.

Bactericidal Effect of TiO2 on the Selected Vibrio Parahaemolyticus and Optimization Using Response Surface Methodology

2007 ◽  
Vol 7 (11) ◽  
pp. 3709-3712 ◽  
Author(s):  
Tae-Young Kim ◽  
Kyung-Hee Park ◽  
Seon-Gyun Rho ◽  
Seung-Jai Kim ◽  
Sung-Young Cho
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Vibrio Parahaemolyticus ◽  
Pathogenic Bacteria ◽  
Uv Light ◽  
Bactericidal Effect ◽  
Illumination Time ◽  
Box Behnken Design ◽  
Uv Illumination ◽  
Typical Food

In this work, the bactericidal effect of TiO2 on selected typical food pathogenic bacteria, Vibrio parahaemolyticus was studied. V. parahaemolyticus is an important pathogen of humans and aquacultured animals. We established the response surface methodology (Box-Behnken Design) to investigate the effect of principal parameters on the cell sterilization such as TiO2 concentration, UV illumination time, temperature, and pH. The sterilization rate reached maximum value at the TiO2 concentration of 1.0 mg/ml. During irradiation under the time of 30 min with UV light with the 1g-TiO2/l, the sterilization rate was greater than 85%, and 99% or more cell lost their viability with 3 hours of irradiation. Sterilization rate of the cell increased with decrease in the pH and temperature.

Optical and Electrical Characterizations of Nanoscale Robust 3C-SiC Membrane for UV Sensing Applications

2018 ◽  
Vol 775 ◽  
pp. 278-282
Author(s):  
A.R.M. Foisal ◽  
T. Dinh ◽  
A. Iacopi ◽  
L. Hold ◽  
E.W. Streed ◽  
...  
Keyword(s):  
Uv Light ◽  
Optical Characterization ◽  
Considerable Change ◽  
Electrical Contacts ◽  
Si Substrate ◽  
Uv Illumination ◽  
Sensing Applications ◽  
Transmission Measurements ◽  
Electrical Characterizations

This paper presents the fabrication and optical characterization of an ultrathin 3C-SiC membrane for UV light detection. SiC nanoscale film was grown on Si substrate and subsequently released to form a robust membrane with a high aspect ratio of about 5000. Transmission measurements were performed to determine the thickness of the film with a high accuracy of 98%. We also employed a simple and highly effective direct wirebonding technique to form electrical contacts to the SiC membrane. The considerable change in the photocurrent of the SiC membrane was observed under UV illumination, indicating the potential of using 3C-SiC membranes for UV detection.

Enhanced Oxidation of Air Contaminants on an Ultra-Low Density UV-Accessible Aerogel Photocatalyst

1996 ◽  
Vol 454 ◽  
Author(s):  
M. Dreyer ◽  
G. K. Newman ◽  
L. Lobban ◽  
S. J. Kersey ◽  
R. Wang ◽  
...  
Keyword(s):  
Reaction Rate ◽  
Adsorption Equilibrium ◽  
Uv Light ◽  
Equilibrium Constants ◽  
Main Stream ◽  
Low Density ◽  
Air Contaminants ◽  
Reaction Rate Constants ◽  
Air Contaminant ◽  
Type Rate

ABSTRACTThis research developed new forms of photocatalysts that could potentially move photocatalytic degradation of air contaminants into the main stream of industrially used remediation technologies. Tests of the photocatalytic activity of the TiO2 aerogel catalysts have been carried out using both acetone and methane as the air contaminant. For comparison, the same tests were carried out on a standard (non-aerogel) anatase powder. Despite having very low crystallinity, the aerogel decontaminates the air far more effectively than an equal volume of the anatase powder which indicates that a much larger fraction of the aerogel is activated by the UV light. Experimental data were used to determine adsorption equilibrium constants for acetone, and to determine reaction rate constants assuming a Langmuir-Hinshelwood type rate expression.

scholarly journals CuO/ZnO Heterojunction Nanorod Arrays Prepared by Photochemical Method with Improved UV Detecting Performance

Nanomaterials ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 790
Author(s):  
Jieni Li ◽  
Tingting Zhao ◽  
Mandar M. Shirolkar ◽  
Ming Li ◽  
Haiqian Wang ◽  
...  
Keyword(s):  
Deposition Process ◽  
Zno Nanorod ◽  
Nanorod Arrays ◽  
Zno Nanorod Arrays ◽  
Illumination Time ◽  
Uv Illumination ◽  
Photochemical Method ◽  
Photochemical Deposition ◽  
Photo Response ◽  
Response Performance

CuO/ZnO heterojunction nanorod arrays were synthesized using a facile photochemical deposition strategy. The morphology of CuO was related to the concentration of Cu2+ in the Cu(NO3)2 solution, UV illumination time, and the air annealing temperature. A possible reaction mechanism was proposed. In the photochemical deposition process, the OH− was generated in the vicinity of the ZnO nanorod arrays and reacted with Cu2+ and NO3− in the solution to form Cu2(NO3)(OH)3/ZnO heterojunction nanorod arrays firstly, which were converted into CuO/ZnO heterojunction nanorod arrays completely after air annealing at a low temperature. The fabricated CuO/ZnO heterojunction nanorod arrays exhibits a well-defined rectifying characteristic and an improved photo-response performance compared with pure ZnO nanorod arrays.

Chemical Precipitation Synthesis of Nano-Crystalline Mg(OH)2

2012 ◽  
Vol 1481 ◽  
pp. 45-52
Author(s):  
A. Medina ◽  
L. Béjar ◽  
G. Herrera-Pérez
Keyword(s):  
Fourier Transform ◽  
Synthesis Method ◽  
Chemical Precipitation ◽  
X Ray Diffraction ◽  
Nano Crystalline ◽  
Transmission Electron ◽  
Particle Size And Morphology ◽  
Precipitation Synthesis ◽  
Size And Morphology ◽  
Analytical Tools

ABSTRACTMagnesium hydroxide (Mg(OH)2) nanoparticles were synthesized by chemical precipitation synthesis method. The influence of the nano-sized Mg(OH)2 on the structural modification was evaluated. The formation of Mg(OH)2 crystals were evaluated by Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA). The particle size and morphology of Mg(OH)2was confirmed by high resolution transmission electron microscopy (HRTEM). The crystalline structure of nanoparticles was characterized by fast Fourier transform (FFT) and X-Ray diffraction (XRD), like analytical tools.

Photoinduced hydrophilicity and photocatalytic decomposition of endocrine-disrupting chemical pentachlorophenol on hollandite

2003 ◽  
Vol 18 (5) ◽  
pp. 1046-1053 ◽  
Author(s):  
Toshiyuki Mori ◽  
Mamoru Watanabe ◽  
Hiromitsu Nakajima ◽  
Masaru Harada ◽  
Kenjiro Fujimoto ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Properties ◽  
Aromatic Compounds ◽  
Photocatalytic Decomposition ◽  
Hydroxyl Groups ◽  
Endocrine Disrupting Chemical ◽  
Oxidative Decomposition ◽  
Uv Illumination ◽  
Endocrine Disrupting ◽  
Photoinduced Hydrophilicity

Surface properties and photocatalytic oxidation reactions on the hollandite-type compound K2Ga2Sn6O16 (KGSO) were examined for photoinduced hydrophilicity and oxidative decomposition of an endocrine-disrupting chemical, pentachlorophenol (C6Cl5OH, PCP), under ultraviolet (UV) illumination. The thin films and mesoporous powders of hollandite were used for examination of surface properties and photocatalysis, respectively. The photoinduced surface property was examined by measurement of the contact angle of water, ortho-chlorophenol (o-C6H4ClOH), and toluene on the surface of KGSO. The contact angle of H2O and o-C6H4ClOH decreased to 0° under UV illumination. The toluene showed little change in contact angle under UV irradiation. It is concluded that the surface of KGSO shows photoinduced hydrophilicity for H2O and aromatic compounds with hydroxyl groups (−OH). In addition, KGSO clearly showed a photo-oxidative decomposition of PCP under weak UV illumination at room temperature. The decomposition speed of C6Cl5OH on KGSO was much faster than that on previous reported nano-sized SnO2 photocatalysts. It is expected that photo-oxidative decomposition of aromatic compound will be controlled by a combination of optimum composition of the hollandite phase and control of the morphology of the hollandite particles. This suggests that hollandite would be a promising photocatalyst for decomposition of aromatic compounds in endocrine-disrupting chemicals.

scholarly journals Mechanochemical synthesis of bismuth ferrite

2013 ◽  
Vol 49 (1) ◽  
pp. 27-31 ◽  
Author(s):  
Z. Marinkovic-Stanojevica ◽  
L. Mancic ◽  
T. Sreckovic ◽  
B. Stojanovic
Keyword(s):  
Milling Time ◽  
Structure Refinement ◽  
Bismuth Ferrite ◽  
Renewable Energy Sources ◽  
Microstructural Analysis ◽  
Three Dimensional ◽  
Conventional Solid State Reaction ◽  
Refinement Method ◽  
Crystallite Sizes ◽  
Size And Morphology

A powder mixture of Bi2O3 and Fe2O3 was mechanically treated in a planetary ball mill in an air from 30 to 720 minutes. It was shown that the mechanochemical formation of BiFeO3 (BFO) phase was initiated after 60 min and its amount increased gradually with increasing milling time. A detailed XRPD structural analysis is realized by Rietveld?s structure refinement method. The resulting lattice parameters, relative phase abundances, crystallite sizes and crystal lattice microstrains were determined as a function of milling time. Microstructural analysis showed a little difference in morphology of obtained powders. The primary particles, irregular in shape and smaller than 400 nm are observed clearly, although they have assembled together to form agglomerates with varying size and morphology. Dense BFO ceramics were prepared by conventional solid-state reaction at the temperature of 810?C for 1h followed immediately by quenching process. [Projekat Ministarstva nauke Republike Srbije, br. III45007: Zero- to Three-Dimensional Nanostructures for Application in Electronics and Renewable Energy Sources: Synthesis, Characterization and Processing

scholarly journals Incorporation of silver (I) ions within zeolite cavities and their photocatalytic reactivity for the decomposition ofN2OintoN2andO2

2003 ◽  
Vol 5 (1) ◽  
pp. 17-19 ◽  
Author(s):  
Woo-Sung Ju ◽  
Masaya Matsuoka ◽  
Masakazu Anpo
Keyword(s):  
Ion Exchange ◽  
Uv Light ◽  
Photocatalytic Decomposition ◽  
Effective Wavelength ◽  
In Situ Characterization ◽  
Exchange Method ◽  
Ft Ir ◽  
Ion Exchange Method

Ag+/ZSM-5 catalysts were prepared by an ion-exchange method. UV-irradiation of theAg+/ZSM-5 catalysts in the presence ofN2Oled to the photocatalytic decomposition ofN2OintoN2andO2at 298 K. Investigations of the effective wavelength of the irradiated UV-light for the reaction as well as the in-situ characterization of the catalysts by means of UV-Vis, photoluminescence and FT-IR spectroscopies revealed that the photoexcitation of theAg+−N2Ocomplexes formed between gaseousN2Oand the isolatedAg+ions exchanged within the zeolite cavities plays a significant role in the reaction.

scholarly journals Fast Synthesis of Co3O4 by Microwave-Assisted Hydrothermal Treatment

2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Midilane S. Medina ◽  
Alessandra Zenatti ◽  
Marcia T. Escote
Keyword(s):  
Magnetic Measurements ◽  
Simple Procedure ◽  
Particle Morphology ◽  
Weak Ferromagnetism ◽  
Oxidizing Agent ◽  
Synthesis Time ◽  
Microwave Assisted ◽  
Crystallite Sizes ◽  
Paramagnetic Behaviour ◽  
Size And Morphology

This work describes a fast and simple procedure that combines the virtues of the microwave-assisted hydrothermal method with an oxidizing agent to produce Co3O4 nanocubes and nanoplates. We observed that particle morphology and size depend on the synthesis time and oxidizing agent (urea and hydrogen peroxide). The X-ray diffraction results showed that the samples are single phase, with crystallite sizes of approximately 30 nm. A similar crystalline domain is observed in the transmission electronic images. Magnetic measurements revealed the influence of the size and morphology of the particles on the magnetic curves. These measurements on the nanoplate samples revealed a paramagnetic behaviour at higher temperatures, and the presence of a cusp at that temperature was defined as TP. The TP decreases from 36 K to 21 K when the size of the plate particles decreases from ~70 nm to 10 nm. These samples also present weak ferromagnetism below TP, which is attributed to a superparamagnetic blockade state. The nanocube samples have a lower magnetic susceptibility magnitude and weak ferromagnetism behaviour at room temperature. Our results show that this synthesis produces Co3O4 nanoplates and nanocubes with interesting magnetic properties related to their shape and size.

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